In vitro diagnostics (IVD) allows labs to assist in the diagnosis of disease based on assays performed on patient fluid samples. IVD includes various types of analytical tests and assays related to patient diagnosis and therapy that can be performed by analysis of a liquid sample taken from a patient's bodily fluids, or abscesses. These assays are typically conducted with automated clinical chemistry analyzers (analyzers) onto which fluid containers, such as tubes or vials containing patient samples have been loaded. The analyzer extracts a liquid sample from the vial and combines the sample with various reagents in special reaction cuvettes or tubes (referred to generally as reaction vessels). In some conventional systems, a modular approach is used for analyzers. A lab automation system can shuttle samples between one sample processing module (module) and another module. Modules may include one or more stations, including sample handling stations and testing stations (e.g., a unit that can specialize in certain types of assays or can otherwise provide testing services to the larger analyzer) which may include immunoassay (IA) and clinical chemistry (CC) stations. Some traditional IVD automation track systems comprise systems that are designated to transport samples from one fully independent module to another standalone module. This allows different types of tests to be specialized in two different stations or allows two redundant stations to be linked to increase the volume of sample throughput available. These lab automation systems, however, are often bottlenecks in multi-station analyzers. Relatively speaking, traditional lab automation systems lack large degrees of intelligence or autonomy to allow samples to independently move between stations.
In an exemplary prior art system, a friction track, much like a conveyor belt, shuttles individual carrier mechanisms, sometimes called pucks, or racks of containers between different stations. Samples may be stored in sample containers, such as in test tubes that are placed into a puck by an operator or robot arm for transport between stations in an analyzer along the track. This friction track, however, can only move in one direction at a time and any samples on the track will move in the same direction at the same speed. When a sample needs to exit the friction track, gating/switching can be used to move individual pucks into offshoot paths (sometimes called sidecars or pullouts). A drawback with this set-up is that singulation must be used to control the direction of any given puck at each gate and switch. For example, if two pucks are near one another and only one puck should be redirected into an offshoot path, it becomes difficult to control a switch so that only one puck is moved into the offshoot path and ensure that the proper puck is pulled from the friction track. This has created the need in many prior art systems to have pucks stop at a gate so that individual pucks can be released and switched one at a time at each decision point on a track. Because the transition between main tracks and sidecar/pullout tracks is slow, queues can build up at decision points at the junction of the main track and sidecar, in addition to the queues that build up on sidecar/pullout tracks.
Traditional linear tracks lack precision or intelligence for providing intelligent transport queuing. While a traditional linear track may be suitable for handling samples on a first-in-first-out (FIFO) basis, other mechanisms are needed to handle samples if random access is needed. For example, carousels may be used to selectively interact with samples in a ring. By rotating the ring, an arbitrary sample can be selected. However, the carousel approach has certain drawbacks. The needed space requirements grow as the square of the number of samples a carousel can hold, and it requires a large round area. Furthermore, carousels may require slow mechanisms to load and unload a sample from a carousel. In addition, the centrifugal forces applied to samples in a carousel can limit the speed at which a carousel operates.
Another drawback of sample queues in prior art tracks is that they may encounter problems when a STAT sample arrives. Even if FIFO access is satisfactory for non-STAT samples, when a STAT sample arrives, a queue may need to be flushed so that a STAT sample can immediately be handled. Any samples in the queue will generally be dumped from a queue to the main track, where they may encounter traffic and high latency from queues at singulation points on the track, as the dumped samples have to traverse the main track to return to the sidecar from which they were dumped.